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United States Patent | 5,548,195 |
Doran | August 20, 1996 |
A stage positioning apparatus including a stage and a servo control system. The servo control system includes a compensation circuit. The compensation circuit determines the cosine of the angle between the off-axis drive bar and the direction of travel. A voltage, proportional to the cosine, is multiplied by the on-axis drive error signal to develop an off-axis compensation voltage. Each drive's new error signal is compensated by its respective off-axis compensation voltage.
Inventors: | Doran; Samuel K. (Wappingers Falls, NY) |
Assignee: | International Business Machines Corporation (Armonk, NY) |
Appl. No.: | 362676 |
Filed: | December 22, 1994 |
Current U.S. Class: | 318/568.19; 74/480R; 318/625; 318/632 |
Intern'l Class: | G05D 011/08 |
Field of Search: | 318/568.19,568.2,565,560,632,640,625,687,38,649,632 250/548 74/479.01,480 R,490.08,40.09 |
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